Search Publications
Titan's temporal evolution in stratospheric trace gases near the poles
Nixon, Conor A.; Achterberg, Richard K.; Flasar, F. Michael +7 more
We analyze spectra acquired by the Cassini/Composite Infrared Spectrometer (CIRS) at high resolution from October 2010 until September 2014 in nadir mode. Up until mid 2012, Titan's Northern atmosphere exhibited the enriched chemical content found since the Voyager days (November 1980), with a peak around the Northern Spring Equinox (NSE) in 2009.…
The abundance and thermal history of water ice in the disk surrounding HD 142527 from the DIGIT Herschel Key Program
Waters, L. B. F. M.; Woitke, P.; Hony, S. +9 more
Context. The presence or absence of ice in protoplanetary disks is of great importance to the formation of planets. By enhancing solid surface density and increasing sticking efficiency, ice catalyzes the rapid formation of planetesimals and decreases the timescale of giant planet core accretion.
Aims: In this paper, we analyze the compositio…
Star formation laws in the Andromeda galaxy: gas, stars, metals and the surface density of star formation
Barmby, P.; Lianou, S.; Rahmani, S.
We use hierarchical Bayesian regression analysis to investigate star formation laws in the Andromeda galaxy (M31) in both local (30, 155 and 750 pc) and global cases. We study and compare the well-known Kennicutt-Schmidt law, the extended Schmidt law and the metallicity/star formation correlation. Using a combination of Hα and 24 µm emission…
Peak-ring structure and kinematics from a multi-disciplinary study of the Schrödinger impact basin
Kramer, Georgiana Y.; Collins, Gareth S.; Kring, David A. +2 more
The Schrödinger basin on the lunar farside is ~320 km in diameter and the best-preserved peak-ring basin of its size in the Earth-Moon system. Here we present spectral and photogeologic analyses of data from the Moon Mineralogy Mapper instrument on the Chandrayaan-1 spacecraft and the Lunar Reconnaissance Orbiter Camera (LROC) on the LRO spacecraf…
Internetwork magnetic field as revealed by two-dimensional inversions
Danilovic, S.; van Noort, M.; Rempel, M.
Context. Properties of magnetic field in the internetwork regions are still fairly unknown because of rather weak spectropolarimetric signals.
Aims: We address the matter by using the two-dimensional (2D) inversion code, which is able to retrieve the information on smallest spatial scales up to the diffraction limit, while being less suscepti…
Distributions of Quasar Hosts on the Galaxy Main Sequence Plane
Rieke, George H.; Shi, Yong; Zhang, Zhoujian +4 more
The relation between star formation rates (SFRs) and stellar masses, I.e., the galaxy main sequence, is a useful diagnostic of galaxy evolution. We present the distributions relative to the main sequence of 55 optically selected PG and 12 near-IR-selected Two Micron All Sky Survey (2MASS) quasars at z ≤ 0.5. We estimate the quasar host stellar mas…
Testing light-traces-mass in Hubble Frontier Fields Cluster MACS-J0416.1-2403
Liesenborgs, Jori; Mohammed, Irshad; Saha, Prasenjit +2 more
We reconstruct the projected mass distribution of a massive merging Hubble Frontier Fields cluster MACSJ0416 using the genetic algorithm based free-form technique called Grale. The reconstructions are constrained by 149 lensed images identified by Jauzac et al. using HFF data. No information about cluster galaxies or light is used, which makes our…
Flux transfer event observation at Saturn's dayside magnetopause by the Cassini spacecraft
Coates, Andrew J.; Arridge, Christopher S.; Waite, J. Hunter +6 more
We present the first observation of a flux rope at Saturn's dayside magnetopause. This is an important result because it shows that the Saturnian magnetopause is conducive to multiple X-line reconnection and flux rope generation. Minimum variance analysis shows that the magnetic signature is consistent with a flux rope. The magnetic observations w…
On the propagation of a geoeffective coronal mass ejection during 15-17 March 2015
Webb, D. F.; Wang, Yuming; Shen, Fang +11 more
The largest geomagnetic storm so far, called 2015 St. Patrick's Day event, in the solar cycle 24 was produced by a fast coronal mass ejection (CME) originating on 15 March 2015. It was an initially west-oriented CME and expected to only cause a weak geomagnetic disturbance. Why did this CME finally cause such a large geomagnetic storm? We try to f…
ALMA Observations of the Debris Disk of Solar Analog τ Ceti
MacGregor, Meredith A.; Matthews, Brenda C.; Wilner, David J. +4 more
We present 1.3 mm observations of the Sun-like star τ Ceti with the Atacama Large Millimeter/submillimeter Array that probe angular scales of ∼ 1\prime\prime (4 au). This first interferometric image of the τ Ceti system, which hosts both a debris disk and a possible multiplanet system, shows emission from a nearly face-on belt of cold d…